The present invention relates to apparatus for releasably supporting annular members, especially for locating and releasably supporting hollow cylindrical cores of bobbins or reels for web material, such as cigarette paper or the like. More particularly, the invention relates to improvements in apparatus or devices wherein the annular core of a bobbin is slipped onto a rotary spindle or hub preparatory to winding web material onto or withdrawing web material from the core. The invention will be described with reference to apparatus for supporting bobbins of cigarette paper or other web material which is utilized in the tobacco processing industry with the understanding, however, that the apparatus can be used with equal advantage for releasably supporting bobbins of web material which is intended for other uses.
A bobbin of cigarette paper is normally mounted on a carrier which can support several bobbins at a time, especially an expiring bobbin and a fresh bobbin which latter is held in a position of readiness for splicing its web to the running web when the supply of running web on the expiring bobbin is nearly exhausted. As a rule, the annular core of the bobbin is urged against a stop so that it is properly located in the axial position thereof. It is also known to employ spring-biased fingers which urge the core axially against the stop. Reference may be had to U.S. Pat. No. 3,463,519 granted Aug. 26, 1969 to Raymond. The patented apparatus employs three fingers which urge the core against the flange of a rotary hub. The outer diameter of the hub is selected in such a way that it matches the inner diameter of the core.
It has been found that conventional apparatus fail to satisfy all requirements for adequate positioning of a bobbin in such a way that the bobbin is properly located during withdrawal of web material and can be rapidly removed from the spindle when the supply of cigarette paper is exhausted. This also applies for bobbins which store supplies of other types of web material. First of all, it is important to properly center the core of the bobbin on the spindle, regardless of whether or not the outer diameter of the spindle matches the inner diameter of the core. Secondly, the core must be held against axial movements. Such requisites must be met in order to prevent radial and/or axial wobbling of the bobbin during withdrawal of web material. Furthermore, the bobbin must be located and held with a certain force which insures that its core does not slip on the spindle when the latter is decelerated preparatory to replacement of the bobbin. Apparatus for releasably supporting bobbins of cigarette paper or the like are equipped with brakes which maintain the web under tension during withdrawal from the bobbin and insure that the bobbin is rapidly decelerated to zero speed as soon as the tensional stress upon the web decreases to zero. An additional requisite which must be satisfied by such apparatus is that an expired bobbin should be readily removable from the spindle in order to provide room for mounting of a fresh bobbin. This is particularly important in cigarette makers which turn out at least 4,000 cigarettes per minute and wherein the supply of cigarette paper on a fresh bobbin is exhausted within a short interval of time, i.e., the attendant must rapidly replace the expired bobbin with a fresh bobbin during the interval of withdrawal of web material from the expiring bobbin. Finally, an exhausted bobbin should be removable from and a fresh bobbin should be insertable into the apparatus with a minimum of effort because such operation must be carried out at frequent intervals and a fresh bobbin of cigarette paper is a rather heavy and bulky commodity. As mentioned above, heretofore known apparatus fail to meet all or even the majority of the above-enumerated requirements.